Q.

Two non-conducting spheres of radii R1 and R2 and carrying uniform volume charge densities +ρ and −ρ, respectively, are placed such that they partially overlap, as shown in the figure. At all points in the overlapping region                    [2013]

1 The electrostatic field is zero  
2 The electrostatic potential is constant  
3 The electrostatic field is constant in magnitude  
4 The electrostatic field has the same direction   

Ans.

(3, 4)

Electrostatic field at P is

E→P=E→1+E→2=ρ3ε0C1P→+(-ρ)3ε0 C2P→

=ρ3ε0(C1P→-C2P→)=ρ3ε0(C1P→+PC2→)=ρ3ε0 (C1C2→)